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84' Nissan 720, Wiring, and Electric Choke Issue


Guest junkyardjameson

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Guest junkyardjameson

Hello,

 

Recently acquired an 84' Nissan 720, Z24, 5 speed manual, 4x2. Runs and drives good until it warms up.

 

1. Choke heater relay is buzzing, I've read up on this issue and it seems to be a common problem. I verified that my battery and alternator are good.

2. Choke is constantly partially open, the choke will not fully open when warm.

3. Carb wiring is a mess, no idea where to even start.

 

We tried to open the choke fully by hand once the truck warmed up. The engine sputter's and will eventually die.

 

Looking for any suggestions, and advice!

 

Attached are photo's and videos for reference.

 

http://i67.tinypic.com/15s9e94.jpg

 

http://i67.tinypic.com/15s9e94.jpg

 

 

 

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51 minutes ago, junkyardjameson said:

Hello,

 

Recently acquired an 84' Nissan 720, Z24, 5 speed manual, 4x2. Runs and drives good until it warms up.

 

1. Choke heater relay is buzzing, I've read up on this issue and it seems to be a common problem. I verified that my battery and alternator are good.

2. Choke is constantly partially open, the choke will not fully open when warm.

3. Carb wiring is a mess, no idea where to even start.

 

We tried to open the choke fully by hand once the truck warmed up. The engine sputter's and will eventually die.

 

 

 

1. & 2.

 

Disconnect the choke heater. The idle cut solenoid is powered by the ignition key. Power your electric choke by connecting the choke heater (Blue?) wire to the Idle Cut solenoid wire. (Blue/White stripe?)

 

 

 

The problem of the engine dying as the choke is opened....

 

Check that the Idle Cut solenoid has power when the ignition is on. Without power the closed solenoid prevents gas from getting to the idle circuit. It should make an audible click when the ignition is turned on and off.

 

Have you tried turning the idle mixture screw up? This will provide more gas to the idling engine, something the choke is doing now

 

Possibly the idle circuit is blocked with sediment and no fuel can get through to the idle mixture screw. Get a can of carb cleaner that has a red straw for directing the spray. Carefully remove the idle cut solenoid. Watch for the copper washer and there's a pin and spring inside. Don't let them get away. Now unscrew the idle mixture screw but count the number of turns so it can go back exactly. Using the straw spray into the idle cut opening. Spray should come out the mixture screw hole so don't get in your eyes. Now spray backwards by spraying the mixture hole and flushing out the idle cut solenoid hole. When done put the idle mixture screw back and again spray the idle cut opening to flush back into the carburetor. Always get the straw in as far as you can.

 

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Guest junkyardjameson

Okay, so with the key on the idle cut solenoid and electric choke have no power. I took a lead from the battery straight to the solenoid and nothing. The choke relay also has no power.

 

No power is going to the carb.

 

There are 4 wires total going to the carb, 1 to the electric carb, 1 to the idle cut solenoid, and 2 go down on the right bottom side of the carb. (No sure what for)

 

Lost at why nothing has power?

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There is no power to the choke until the engine is running, that's why there's a relay. Not that critical to have the relay as long as power switches on and off with the key. This is why I mentioned connecting to the idle cut. Now all you need do is find out why there is no power to the idle cut solenoid. The idle cut is powered from the second fuse (15A) over from the far left hand side.

 

The other two wires are probably to a heater plate sandwiched between carb and intake.

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Guest junkyardjameson

Fuse was blown, replaced the fuse, and it seems the idle cut solenoid is working now. The electric choke is also working suddenly. Car runs at an idle with the choke open now, and doesn't diesel anymore.

 

It does run better at idle and while driving now, however it still is not running correctly. Lack of power, rough idle, running rich. We messed with the distributor timing, idle set screw, and the air/fuel mixture, we just could not get it running properly.

 

I am assuming the next step is to rebuild/replace the carb and sort out the vacuum lines. 

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1/ I would set check the valve lash.

 

2/ Timing is 3 degrees. Check/clean the plugs.

 

3/ Adjust idle mix screw in or out with the idle speed turned down. There is about a 1/2 turn where it runs best.... just set roughly in the middle of the 'runs well' range. Turn idle down and repeat till you cannot improve the idle and the idle speed is about 750. Do this with a warmed up engine choke off and 1/ and 2/ done first.

 

It's been out of whack for a while so drive it around to burn off any carbon from the choke being on.

Look for any other vacuum leaks or cracked hoses. Pinch hoses with pliers.... see if idle comes up.

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Guest junkyardjameson

Okay, I plan on checking/setting the valve lash this weekend. Timing is set to 3 degrees we made sure of that, and I'll probably just go ahead and replace the plugs and wires.

 

Is the 32/36 Weber conversion worth the money vs rebuilding the OE carburetor?

 

 

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